This invention relates generally to medical electrical leads and more, particularly to implantable leads for use in cardioverting or defibrillating the heart.
Implantable cardioverters and defibrillators, as presently available, are of substantial size, with the result that in most cases the devices are implanted in the abdominal region, rather than in the pectoral region as typically employed for cardiac pacemakers. As a result, the distance from the defibrillator or cardioverter to the location of the electrode in the heart is substantially greater than would be the case in a corresponding pectoral implant. In systems employing transvenous leads, the leads are tunnelled subcutaneously for a substantial distance between the site of venous insertion to the device implant site.
In the context of cardiac pacing, abdominal implants of pulse generators have also been employed, and in some cases, in order to accommodate the increased distance between the pulse generator and the electrode in the heart, lead extenders have been employed. Typically, such extenders have included a receptacle at one end, for receiving the connector pin of the pacing lead and have employed a connector pin at the other end, corresponding to the connector pin of the pacing lead. For example, Medtronic, Inc. has manufactured and sold such lead extenders, Model Nos. 6981 and 6981M, for some time.
Lead extenders and similar devices have also been employed to repair previously implanted leads having broken or damaged connector pins and/or lead bodies. For example, such repair kits are illustrated in U.S. Pat. No. 5,036,862 issued to Pohndorf, U.S. Pat. No. 5,060,649 issued to Hocherl et al., U.S. Pat. No. 4,954,105 issued to Fischer and U.S. Pat. No. 4,466,690 issued to Osypka.
Generally, when lead extenders are employed, they are coupled to the electrode lead after its implantation within the heart. The lead extender is thereafter tunneled subcutaneously or otherwise routed through the body to the implantable pulse generator.